1. Field of the Invention
This invention relates generally to equipment for testing electronic devices and busses, and, more particularly, to test equipment that is adaptable for testing devices and digital busses covering a wide range of bus interface specifications.
2. Description of Related Art
The military and the commercial sector commonly employ digital busses for controlling electronic systems. Different types of busses are used in different applications. For instance, commercial aircraft commonly use ARINC 429 busses for avionics systems, while the military commonly uses MIL-STD-1553 busses for controlling aircraft and weapons systems. The commercial sector commonly uses RS-232 busses for computer applications. In addition, military and commercial entities often develop custom busses, with proprietary interface specifications and protocols, for enabling communication among different elements of in-house systems.
Manufacturers of devices for digital busses often use automatic test equipment (ATE) to verify device performance. Customarily, this test equipment is designed specifically for a particular bus type. For instance, specialized ARINC 429 instruments are employed for testing ARINC 429 devices, whereas specialized MIL-STD-1553 instruments are used for testing 1553 devices. Manufacturers of proprietary busses often develop custom test equipment for testing their custom bus devices. Alternatively, they may adapt general-purpose digital test equipment to suit their particular testing needs.
The specialization in bus test equipment is attributable in part to the fact that interface specifications for different bus types vary widely. Different busses can operate at different frequencies, edge speeds, and/or voltage levels. Busses can be unidirectional or bidirectional, single-ended or differential. Some busses provide handshaking and/or clock lines; some do not.
Despite these differences, we have recognized that the testing problems posed by digital busses are essentially similar across different types of busses, and that manufacturers could benefit from a more universal approach to bus testing.